Car Fix DIY Videos

The starter alternator is a component in the charging system of a vehicle that combines the functions of both a starter motor and an alternator. It is used to start the engine and also to generate electricity to charge the battery and power the electrical systems while the engine is running. In a Mercedes-Benz vehicle with the M256.9 engine, the starter alternator is responsible for providing the electrical power needed to start the engine, as well as keeping the battery charged and powering the vehicle’s electrical systems while the engine is running.
It is located on the front of the engine and connected to the crankshaft.
It is possible that the starter alternator may have to be replaced if it fails. Symptoms of a failing starter alternator can include a dead battery, dimming headlights, and difficulty starting the engine. It is important to diagnose the problem correctly and replace the part with the correct one for the vehicle to ensure proper performance and avoid damage to other components.

This video describes the process of removing and installing the integrated starter alternator (ISG) on Mercedes-Benz vehicles with the M256.9 engine. It explains that before the ISG can be removed, the transmission and ISG control unit must be taken out, as well as various other components such as the sensors of the intake and exhaust camshaft, the hose to the air filter, and the crankshaft sensor. It also provides detailed instructions on how to properly position and secure the ISG during the installation process, including the use of specific torque values and rotation angles as specified in the WIS (Workshop Information System) document. Additionally, it mentions the need for inspection of the ISG, including checking the air gap between the stator and rotor and measuring the phase resistance of the coils.

Part # : AR15.40-P-0003MRT